A plasma tube array (PTA) and a plasma display panel (PDP) are known as a thin color display device employing discharge-induced light-emission elements. (See JP 2004-178854-A.)
G. Oversluizen et al. disclose, in “5.1 High Efficiency PDP”, SID (Society for Information Display), 03 DIGEST, 2003, pp. 28-31, that the emission efficiency and luminosity of a PDP can be increased by providing a layer of titanium dioxide (TiO2) under a phosphor layer of the PDP.